Isuzu AU-4LE1T, Maintenance Manual

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3. FUEL SYSTEM
The fuel injection pump and fuel injection nozzle are precisely
manufactured, and therefore, using the fuel which contains water or dust
particles will result in either injection pump plunger seizure or injection
nozzle seizure, and the fouled fuel filter element with sludge or dust
particles lead to decreased engine output.
In addition, clogged filter element can cause low output or automatic air
bleeding failure.
Perform inspection and maintenance periodically as follows:
(1) Removal of Water from the Fuel
The water sedimenter is provided to separate the water contained in
the fuel.
The sedimenter housing contains a float which moves up and down in
accordance with level change of the separated water.
Be sure to drain the separated water when the float has come up to the
element part.
Draining procedure:
With the water sedimenter lever positioned just above the fuel remains
off, loosen the air bleeding plug at the top of the water sedimenter, and
then loosen the drain plug at the bottom of the case to drain the
separated water.
After draining, be sure to tighten the plugs and conduct air bleeding of
fuel.
Be careful not to over-tighten the air bleeding plug.
Torque (Drain plug) :
1.0 to 2.0 Nm (0.1 to 0.2 kgm)
Torque (Air bleeding plug) : 1.5 to 3.0 Nm (0.15 to 0.31 kgm)
Lever
Drain plug
Element
Float
Air bleeding plug
IMLE0057